# Natural Frequencies

**URL:** <https://forum.cadmunity.com/t/natural-frequencies/81>\
**Category:** Computer Aided Engineering\
**Created:** [March 10, 2021, 7:27am UTC](https://forum.cadmunity.com/t/natural-frequencies/81 "2021-03-10T07:27:59Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jayar](https://forum.cadmunity.com/user_avatar/forum.cadmunity.com/jayar/32/16_2.png) [@jayar](https://forum.cadmunity.com/u/jayar)\
**Post date:** [March 10, 2021, 7:27am UTC](https://forum.cadmunity.com/t/natural-frequencies/81/1 "2021-03-10T07:27:59Z")

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I thought I knew how to get the first few harmonics for a body but the results only show the first 5 modes. The way I understand things, the first 6 modes are body modes and not ‘real’ natural frequencies as we’d like to identify.

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**Author:** ![Frederick\_Law](https://forum.cadmunity.com/user_avatar/forum.cadmunity.com/frederick_law/32/8_2.png) [@Frederick\_Law](https://forum.cadmunity.com/u/Frederick_Law)\
**Post date:** [March 10, 2021, 7:50pm UTC](https://forum.cadmunity.com/t/natural-frequencies/81/2 "2021-03-10T19:50:33Z")

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I believe they all multiple of first mode.  
I just get first mode higher then machine RPM to avoid harmonic.

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**Author:** ![jayar](https://forum.cadmunity.com/user_avatar/forum.cadmunity.com/jayar/32/16_2.png) [@jayar](https://forum.cadmunity.com/u/jayar)\
**Post date:** [March 20, 2021, 9:33am UTC](https://forum.cadmunity.com/t/natural-frequencies/81/3 "2021-03-20T09:33:25Z")

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I know that the first 6 modes are ‘body’ modes - not natural frequencies.  
Figured out I had to restrain the model to get the natural frequencies but still wondering why I can’t see the higher order ones.